1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Copyright (C) 1996-2000 Russell King - Converted to ARM. |
4 | * Original Copyright (C) 1995 Linus Torvalds |
5 | */ |
6 | #include <linux/cpu.h> |
7 | #include <linux/delay.h> |
8 | #include <linux/reboot.h> |
9 | |
10 | #include <asm/cacheflush.h> |
11 | #include <asm/idmap.h> |
12 | #include <asm/virt.h> |
13 | #include <asm/system_misc.h> |
14 | |
15 | #include "reboot.h" |
16 | |
17 | typedef void (*phys_reset_t)(unsigned long, bool); |
18 | |
19 | /* |
20 | * Function pointers to optional machine specific functions |
21 | */ |
22 | void (*pm_power_off)(void); |
23 | EXPORT_SYMBOL(pm_power_off); |
24 | |
25 | /* |
26 | * A temporary stack to use for CPU reset. This is static so that we |
27 | * don't clobber it with the identity mapping. When running with this |
28 | * stack, any references to the current task *will not work* so you |
29 | * should really do as little as possible before jumping to your reset |
30 | * code. |
31 | */ |
32 | static u64 soft_restart_stack[16]; |
33 | |
34 | static void __soft_restart(void *addr) |
35 | { |
36 | phys_reset_t phys_reset; |
37 | |
38 | /* Take out a flat memory mapping. */ |
39 | setup_mm_for_reboot(); |
40 | |
41 | /* Clean and invalidate caches */ |
42 | flush_cache_all(); |
43 | |
44 | /* Turn off caching */ |
45 | cpu_proc_fin(); |
46 | |
47 | /* Push out any further dirty data, and ensure cache is empty */ |
48 | flush_cache_all(); |
49 | |
50 | /* Switch to the identity mapping. */ |
51 | phys_reset = (phys_reset_t)virt_to_idmap(cpu_reset); |
52 | |
53 | /* original stub should be restored by kvm */ |
54 | phys_reset((unsigned long)addr, is_hyp_mode_available()); |
55 | |
56 | /* Should never get here. */ |
57 | BUG(); |
58 | } |
59 | |
60 | void _soft_restart(unsigned long addr, bool disable_l2) |
61 | { |
62 | u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack); |
63 | |
64 | /* Disable interrupts first */ |
65 | raw_local_irq_disable(); |
66 | local_fiq_disable(); |
67 | |
68 | /* Disable the L2 if we're the last man standing. */ |
69 | if (disable_l2) |
70 | outer_disable(); |
71 | |
72 | /* Change to the new stack and continue with the reset. */ |
73 | call_with_stack(fn: __soft_restart, arg: (void *)addr, sp: (void *)stack); |
74 | |
75 | /* Should never get here. */ |
76 | BUG(); |
77 | } |
78 | |
79 | void soft_restart(unsigned long addr) |
80 | { |
81 | _soft_restart(addr, disable_l2: num_online_cpus() == 1); |
82 | } |
83 | |
84 | /* |
85 | * Called by kexec, immediately prior to machine_kexec(). |
86 | * |
87 | * This must completely disable all secondary CPUs; simply causing those CPUs |
88 | * to execute e.g. a RAM-based pin loop is not sufficient. This allows the |
89 | * kexec'd kernel to use any and all RAM as it sees fit, without having to |
90 | * avoid any code or data used by any SW CPU pin loop. The CPU hotplug |
91 | * functionality embodied in smp_shutdown_nonboot_cpus() to achieve this. |
92 | */ |
93 | void machine_shutdown(void) |
94 | { |
95 | smp_shutdown_nonboot_cpus(primary_cpu: reboot_cpu); |
96 | } |
97 | |
98 | /* |
99 | * Halting simply requires that the secondary CPUs stop performing any |
100 | * activity (executing tasks, handling interrupts). smp_send_stop() |
101 | * achieves this. |
102 | */ |
103 | void machine_halt(void) |
104 | { |
105 | local_irq_disable(); |
106 | smp_send_stop(); |
107 | while (1); |
108 | } |
109 | |
110 | /* |
111 | * Power-off simply requires that the secondary CPUs stop performing any |
112 | * activity (executing tasks, handling interrupts). smp_send_stop() |
113 | * achieves this. When the system power is turned off, it will take all CPUs |
114 | * with it. |
115 | */ |
116 | void machine_power_off(void) |
117 | { |
118 | local_irq_disable(); |
119 | smp_send_stop(); |
120 | do_kernel_power_off(); |
121 | } |
122 | |
123 | /* |
124 | * Restart requires that the secondary CPUs stop performing any activity |
125 | * while the primary CPU resets the system. Systems with a single CPU can |
126 | * use soft_restart() as their machine descriptor's .restart hook, since that |
127 | * will cause the only available CPU to reset. Systems with multiple CPUs must |
128 | * provide a HW restart implementation, to ensure that all CPUs reset at once. |
129 | * This is required so that any code running after reset on the primary CPU |
130 | * doesn't have to co-ordinate with other CPUs to ensure they aren't still |
131 | * executing pre-reset code, and using RAM that the primary CPU's code wishes |
132 | * to use. Implementing such co-ordination would be essentially impossible. |
133 | */ |
134 | void machine_restart(char *cmd) |
135 | { |
136 | local_irq_disable(); |
137 | smp_send_stop(); |
138 | |
139 | do_kernel_restart(cmd); |
140 | |
141 | /* Give a grace period for failure to restart of 1s */ |
142 | mdelay(1000); |
143 | |
144 | /* Whoops - the platform was unable to reboot. Tell the user! */ |
145 | printk("Reboot failed -- System halted\n" ); |
146 | while (1); |
147 | } |
148 | |